Assign multiline string to variable in script [duplicate]

I want a variable, let’s say PS, defined in my .profile file with the following value:

PS1='PWD: ${PWD}
$ '

So that when I enter $PS in my terminal, I get a two-lined prompt string, the first line showing my working directory. How can I define this in my .profile file?

Edit: the question that this is purportedly a duplicate of is not the same at all. My question is about assigning a multiline value to a variable in a shell script. Neither \n nor \ followed by Enter appear to work. Note that the assignment I wrote works perfectly well interactively. In fact, I have it saved it in my OneNote and often copy/paste it in my shell. But I would like it to be in my .profile file or another script so I can skip this step, and writing it as is in a script does not work. Finally, if someone suggests a change where PS1 is changed automatically, that is OK, but the ideal would be if the whole thing above was assigned to a variable like PS so that when I typed $PS, PS1 would be set.

Edit 2: I found a solution. In .profile:

PS1="PWD: ${PWD}
\$ "

This changes PS1 only when I run . .profile Which is weird because I know .profile is being run in some way on startup (I try echoing variables that are defined in .profile before running it and they exist; I’m guessing there is some other file that is being run automatically after .profile that sets PS1 to the default one-liner), but I guess it’s what I want because I want some control over whether my change is effective. If I want my change to be effective I run . .profile, if not I don’t do anything. Sorry for the confusion, I was trying to experiment and update the description as fast as I could!